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    <title>Document</title>

    <script>
        // 下面是代码 1 部分------
        let s = new Set();
        [1,1,2,3,4,4].forEach (x => s.add(x));
        for (let i of s) {
            console.log(i)
        }

        // 下面是代码 2 部分---------------
        let set1 = new Set ([1,1,2,3,4,4])
        console.log(set1);
        // 下面是代码 3 部分----
        let arr1 = [1,2,3];
        let arr2 = [2,3,4,5];
        let set2 = new Set ([...arr1, ...arr2])
        console.log(set2)

        // 下面是代码 4 部分----------------
        console.log([...new Set('ababbc')].join(''));
    </script>
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